Pick Your Porcine Poison

April 13, 2009

What if free-range pork, grown without antibiotics, actually posed more of a health risk than pork produced on industrial farms? That’s what James McWilliams suggested last week in an a New York Timesop-ed, in which he discusses a study by an Ohio State University researcher who found that pigs raised in free-range, antibiotic-free environments tested positive for three food-borne pathogens—salmonella, toxoplasma, and trichinella—at significantly higher rates than their conventionally raised cousins.

Granted, McWilliams has a record of hostility towards the organic food movement—he’s written a forthcoming book on how “locavores are endangering the future of food”—and the study he cites was funded by the National Pork Board, a trade group for conventional pig farmers. There’s even some question of whether the free-range pigs that tested positive for food-borne pathogens were actually infected or simply had antibodies present in their blood due to earlier infections that they managed to fight off. But, that said, it stands to reason that pigs raised in the absence of bacteria-killing antibiotics are going to be more likely to harbor bacteria such as salmonella and toxoplasma. (It also stands to reason that pigs that are free to roam outdoors would have more chance of contracting non-bacterial trichinella, which can be carried by wild animals.) If anything, it’d be more surprising if the study had found that antibiotic-free pigs didn’t test positive for these pathogens at a significantly higher rate.

Does it follow that reducing antibiotic use on hog farms isn’t such a great idea? Only if you’re looking at the question solely from a product-safety perspective. If you’re a consumer looking to reduce your risk of getting sick from pork, perhaps it makes sense to buy conventional. (It’s worth noting, though, that even if pork is contaminated with salmonella or trichinosis, cooking it to the USDA-recommended 160 degrees should make it perfectly safe to eat.) But the real reason that we shouldn’t be using antibiotics on pig farms has nothing to do with protecting those who want to eat their pork a little rare. It has to do with protecting society as a whole from the threat of antibiotic-resistant bacteria.

Antibiotic use in livestock turns out to be a classic example of the tragedy of the commons. It’s in everyone’s best interest for antibiotics to retain their effectiveness. It’s bad news for everyone to have pig farms breeding antibiotic-resistant strains of Staphylococcus and other nasty bacteria, which is exactly what happens in confined feeding operations where farmers use antibiotics on healthy as well as sick pigs. And yet farmers and consumers stand to gain individually—through higher profits and cheaper pork—by pumping pigs full of antibiotics. In the absence of government intervention, a socially-inefficient equilibrium will prevail.

So the big question here is not whether health-conscious individuals should be springing for antibiotic-free pork. The question is how tightly the government ought to be restricting antibiotic use in agriculture. If antibiotic-free pork is in fact more likely to harbor bacteria, coming up with an answer to this question will require balancing the public-health threat posed by food-borne pathogens against the threat of antibiotic-resistant bacteria. Given that food-borne pathogens are fairly easy to get rid of by proper cooking, the proper balance will almost certainly invovle less antibiotic use, not more.